The invention relates to an otoscope including a mounting device in which an ear speculum is releasably attached.
Otoscopes are used for looking into and examining the outer ear canal and usually include a light source and an optical imaging system as well as an ear speculum which is inserted into the ear canal for observation thereof.
For hygienical reasons ear specula are designed to be exchangeable, wherein it is preferable to be able to exchange an ear speculum following a patient examination without having to remove the used and possibly contaminated ear speculum by hand.
DE 20 2008 005 144 U1 discloses an otoscope including an exchangeable ear speculum, the ear speculum being attached to a speculum receptacle, wherein locking noses clampingly engage in recesses in the speculum receptacle. An ejector ring is provided for ejecting the ear speculum, the ejector ring planarly abutting against an end side of the ear speculum. The ejector ring is displaced by means of a rod system in response to the actuation of a pusher. For enabling displacement of the ear speculum by means of the ejector ring, the retention force of the locking noses in the recesses must be limited. This in turn entails that the ear speculum may come off the speculum receptacle during examination.
US 2005/0027168 A1 discloses an otoscope including an ear speculum comprising ramp-shaped engagement members at its lower edge arranged in circumferential direction about the circumference of the speculum. Upon insertion of the ear speculum in the mounting device of the otoscope the ear speculum is twisted about its longitudinal axis, whereby the ramp-like engagement members lockingly engage in corresponding receptacles in the mounting device. By turning a rotary knob at the mounting device the ear speculum is rotated in the opposite direction until the engagement ramp has been moved out of the respective receptacle. Subsequently the ear speculum can be shaken off. Inserting the ear speculum in the mounting device is relatively complicated and thus requires sufficient dexterity of the examining person.
In the case of the otoscope known from US 2005/0027168 A1 as well as in the case of the otoscope disclosed in DE 20 2008 005 144 U1 the ejected ear specula can be reused. This entails the risk that patients are examined with an ear speculum which has already been used before and are exposed to a risk of infection.
The object underlying the invention is to use means of simple design for providing an otoscope including ear specula which are capable of being securely attached and detached in a simple manner, wherein it is preferable that it is impossible to reuse the ear speculum once it has been detached.
This object is achieved by an otoscope comprising a mounting device in which an ear speculum is releasably attached, said ear speculum including a conically tapering cone portion, wherein                said ear speculum comprises a substantially cylindrical base portion being coaxial to said cone portion and having a diameter which is larger than the largest diameter of said cone portion and being connected through an intermediate wall portion to said cone portion;        at least one cutout extending to an free edge of said base portion is formed in said base portion of said ear speculum;        a resilient snap hook is arranged in said at least one cutout, said resilient snap hook comprising a connecting leg having a first and a second end, said first end being connected to said base portion in proximity of said free edge, said connecting leg substantially extending in circumferential direction of said base portion, and a holding leg extending from said second end of said connecting leg towards said intermediate wall portion, wherein an inner side of said snap hook protrudes into an cylinder space of said base portion;        said mounting device comprises an outer collar arranged within said base portion, against which said intermediate wall portion abuts and in which at least one marginal recess is formed through which said snap hook is passed with an inner side under resilient deformation such that after resilient reforming said snap hook engages behind said outer collar next to said marginal recess.        
In the case of the otoscope according to the invention the ear speculum can be attached in a simple manner by placing the ear speculum thereon such that the base portion surrounds the outer collar and the snap hooks are passed with their inner sides through the marginal recesses at the outer collar. When the snap hooks are passed through the marginal recesses, they are resiliently deformed by bending the holding leg towards the edge of the cutout which is connected to the connecting leg. After the snap hook has been passed through the marginal recess, the holding leg is restored to its initial position and therefore engages behind the outer collar. Thus the ear speculum is securely connected to the mounting device and cannot unintentionally become detached.
In an advantageous embodiment a stopper lug is provided which protrudes from the holding leg of the snap hook outwardly in relation to the base portion. Further a rotatable device is provided which can be rotated about the longitudinal axis of the cone portion and which includes at least one recess facing the base portion and being engaged by the stopper lug. When the rotatable device is turned in the appropriate direction, the holding leg is bent back towards the direction of the edge of the cutout such that the snap hook can be passed back through the corresponding marginal recess when the ear speculum is detached.
Said detaching is facilitated if in an advantageous embodiment a through-going recess is formed adjacent to the at least one cutout in the base portion, the height of the through-going recess decreasing in relation to the free edge of the base portion in ramp-like fashion towards the cutout, and if an engagement member is mounted at the rotatable device which engages in the through-going recess. In the case of this embodiment not only the holding leg is deformed such that the snap hook fits through the marginal recess when the rotatable knob is twisted, but also the ear speculum is simultaneously raised by the engagement member sliding along the ramp-like portion and becomes detached automatically from the mounting device.
Preferably the rotatable device is formed by a rotatable knob which coaxially surrounds the base portion and at the inner circumference of which the engagement member is mounted.
In order to prevent reuse of an ear speculum which has been used before, the connecting leg includes a neck or a weakness in the material configured such that the yield point of the material of the snap hook is exceeded thereat when the snap hook is resiliently deformed once again after having reformed. This happens when for detaching the ear speculum the rotatable device is turned, causing the holding leg to be bent such that the snap hook fits through the marginal recess again.
The rotatable device can be automatically moved back to its initial position if the mounting device comprises a resilient device against the spring force of which the rotatable device can be rotated from an initial position.
Advantageously the ear speculum is an integral plastic part, preferably an injection molded part.